First off, you need to know if the original cast crank is still in the engine or was it changed to a forged piece at some point.....If it is the original cast crank you should have a damper on the front that says right on it "use for cast crank 340 only" also originally they had a weighted torque converter and a neutral (no weights ) flex plate ....So to use an aftermarket torque converter (with no weights) you need the weighted flex plate ......I have one setting right in front of me and yes it has the half moon cutout like in the bottom picture but the moon cutout doesn't look as big as the one pictured.....it is a little smaller....I have the B&M one setting in front of me now and if you look directly across from the moon cutout it will have the part number....It should be 10235.....here is a link to a new one on summit
http://www.summitracing.com/parts/bmm-10235
The 360's had a different bob weight than the 340's so they are weighted different
hope I answered your question
